- cosmic rays
- /kɒzmɪk ˈreɪz/ (say kozmik 'rayz)
radiation of extremely high penetrating power originating from various sources outside the earth's atmosphere, consisting principally of charged particles moving at nearly the velocity of light. Low-energy cosmic rays emanate from the sun, but the source of high-energy extragalactic cosmic rays is not known.
Also, cosmic radiation.
Australian English dictionary. 2014.